The measurement of viscosity in automotive, medical, agricultural and industrial applications is important to determine some fluid characteristics that may be related to the fluids performance as a fuel, lubricate, cooling, biological solvent and/or a carrier of substances in different applications.
Currently, several technologies are used to measure viscosity for example, vibrating and frequency excited devices use the principal of a dampening effect to determine the resistance of a fluid to shear stresses, which is then correlated to viscosity. This method is widely used. However, it requires a controller for excitation and is very dependent upon temperature variations and fluid composition.
Another example of technologies used to measure viscosity is microwave propagation in fluid medium. This method is accurate and reliable however, this method also requires a controller and considerable investment in order to accommodate it in smaller packages. In addition, it is also very dependent upon fluid composition. Yet another example of technologies used to measure viscosity is optical detection devices. These are also accurate in a controlled fluid medium. However, it is very dependent upon the fluid composition and its reliability as a sensor is hindered by the formation of solid particles that may obstruct the clearance of the optical sensing element. In addition, this technology is very expensive and is typically used in medical and/or industrial applications.
A common point or disadvantage associated with the aforementioned sensing technologies is that they operate better under low dynamic flow rates or in a completely static state of the medium.